Testing Skills

Overview

Comprehensive testing knowledge for building reliable, maintainable software with confidence in deployments.

Categories

Fundamentals

• Testing Pyramid
• Test-Driven Development (TDD)
• Behavior-Driven Development (BDD)
• Core Testing Principles

Unit Testing

• Test isolation and independence
• Mocking and stubbing strategies
• Test doubles (mocks, stubs, spies, fakes)
• Effective assertions

Integration Testing

• Database integration tests
• API endpoint testing
• External service testing
• Container-based testing

End-to-End Testing

• Browser automation
• Mobile app testing
• Visual regression testing
• Cross-browser testing

Test Patterns

• Arrange-Act-Assert (AAA)
• Given-When-Then
• Test fixtures and factories
• Page Object Model

Advanced Testing

• Property-based testing
• Mutation testing
• Contract testing
• Chaos engineering

Test Pyramid

         ╱╲
        ╱  ╲         E2E Tests
       ╱────╲        (Few, Slow, Expensive)
      ╱      ╲
     ╱────────╲      Integration Tests
    ╱          ╲     (Medium)
   ╱────────────╲
  ╱              ╲   Unit Tests
 ╱________________╲  (Many, Fast, Cheap)

Quick Reference

Test Type	Speed	Scope	Confidence	Cost
Unit	Fast (ms)	Single unit	Low-Medium	Low
Integration	Medium (s)	Multiple units	Medium-High	Medium
E2E	Slow (min)	Full system	High	High

When to Use Each Type

Unit Tests

• Business logic validation
• Algorithm correctness
• Edge case handling
• Pure functions

Integration Tests

• Database operations
• API endpoints
• Service interactions
• Message queues

E2E Tests

• Critical user journeys
• Payment flows
• Authentication
• Cross-service workflows

Directory Structure

skills/testing/
├── _index.md
├── fundamentals/
│   ├── testing-pyramid.md
│   ├── test-driven-development.md
│   ├── behavior-driven-development.md
│   └── testing-principles.md
├── unit-testing/
│   ├── unit-test-basics.md
│   ├── mocking-strategies.md
│   ├── test-doubles.md
│   └── assertion-patterns.md
├── integration-testing/
│   ├── integration-test-basics.md
│   ├── database-testing.md
│   ├── api-testing.md
│   └── external-service-testing.md
├── e2e-testing/
│   ├── e2e-basics.md
│   ├── browser-testing.md
│   ├── mobile-testing.md
│   └── visual-regression.md
├── patterns/
│   ├── arrange-act-assert.md
│   ├── given-when-then.md
│   ├── test-fixtures.md
│   ├── factory-patterns.md
│   └── page-object-model.md
├── advanced/
│   ├── property-based-testing.md
│   ├── mutation-testing.md
│   ├── contract-testing.md
│   └── chaos-testing.md
└── ci-cd/
    ├── test-automation.md
    ├── coverage-reporting.md
    └── flaky-tests.md

Related Skills

• Code Quality
• CI/CD
• Security